Currently many women cannot meet military requirements for heavy and very heavy lifting tasks. The overall goal of this proposal is designed to discover which type of women's strength training is most effective for achieving the result the Army wants. We intend to determine the contribution of upper body strength training to meet this goal. Our strategy will be to then transfer our initial findings to a strength training program for field unit use. For comparison and determination of program effectiveness, a group of 100 untrained men will serve as "standards". Although the study will take three years, the formal training will take six months with testing at three month intervals. The training program utilizes the most advanced programs in resistance training. Tests include neuromuscular strength and power tests, electromyography and magnetic resonance imaging for muscle size. Performance tasks which are uniquely relevant to the military will be performed. We will monitor selected physiological changes which are taking place in the blood of women during and after training. Because we know that many women may not tolerate high intensity training (i.e. the 'overtraining syndrome'), we propose to monitor immune status as an indicator of health. We will also measure certain anbolic hormone levels in the blood of the test subjects because they are known to be key regulators of muscle size and neuromuscular function. We believe that the blood levels of anabolic hormones will change depending upon which of the six training programs is used: if so, we should be able to correlate performance achievement with hormone concentration. The product of this effort would be the development of "blood markers of trainability". Such a product would be extremely useful to achieving the goal of attaining and maintaining women who are able to meet these military requirements. In summary, our training programs will establish: 1) the maximal gains in physical performance that are possible in untrained women; 2) how that maximal performance compares to that of the average male; and 3) markers of health and trainability that could be routinely used in large field training efforts in the future.